Inhaled COVID-19 vaccine shows promising results in animal models

In a new vaccine study, researchers at the University of Iowa and University of Georgia found that an inhaled COVID-19 vaccine was effective at preventing infection and transmission in mice and ferret models.


Ryan Adams

The Roy J. & Lucille A. Carver College of Medicine is seen on Monday, November 18, 2019.

Lillian Poulsen, News Reporter

People might have the option to inhale a COVID-19 vaccine, after clinical trials have shown the effectiveness of an inhaled vaccine in animals to protect against the virus.

A new study led by a team at the University of Iowa and the University of Georgia found that a single-dose intranasal COVID-19 vaccine fully protects mice against lethal virus infection.

The vaccine also prevents transmission between animals, leading the researchers to believe it may be effective in humans.

“The vaccine does the same things that a traditional vaccine does, but it also creates a local immune response in the respiratory tract,” Paul McCray, professor of pediatrics-pulmonary medicine, and microbiology and immunology at the UI Carver College of Medicine said. “Since this is a respiratory virus, that could be an added benefit.”

The vaccine is administered through a nasal spray, unlike the currently available mRNA vaccines that require an injection into the arm, McCray said.

He said the available vaccines — Johnson & Johnson, Pfizer, and Moderna — deliver messenger RNA into a body’s cells and instruct it to make the spike microprotein that is presented to the immune system.

In the case of this intranasal vaccine, parainfluenza virus 5 (PIV5) — a virus that doesn’t cause infection in humans — carries the genetic material into the cell and tells it to make the spike microprotein, McCray said.

The spike microprotein is the part of the coronavirus that binds to the receptor on the host cells, which is the first step of getting into other cells, McCray said. If the body makes antibodies — through a vaccine — against the spike microprotein, that interferes with the ability of the virus to bind to the cells and get in, he said.

The team has found success with this new vaccine in mice and ferret models, McCray said.

“These mice are given the SARS-Cov-2 and they develop a progressive, fatal infection so they die,” he said. “One of the measures of success with this is that we pre-treated them with the vaccine and they all lived.”

Additionally, the mice had less instances of lung disease and the vaccine prevented the spread to the central nervous system, McCray said.

In ferret models tested at the University of Georgia, the team found even more success, Biao He, professor of infectious diseases at the University of Georgia College of Veterinary Medicine said.

The ferrets are a good model for humans due to their similar respiratory systems, he said.

“The vaccine prevented infection and transmission among ferrets… generates very good mucosal responses in the airways of animals,” he said. “It’s very exciting, because I don’t believe anyone else has been able to achieve this level of protection before.”

McCray said the success in animal studies makes the team excited for the potential in humans.

“We’re really excited about these animal studies, because they are proof that this vaccine could be protective,” McCray said. “We’re really excited that it works in these animals and now we need to test it in the most important animal — humans.”

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The team has recently received FDA clearance to begin testing the vaccine in humans, He said. The initial trial will be at three sites in the U.S.: Rochester, New York; Cincinnati, Ohio; and Bardstown, Kentucky; and the first patient will receive the vaccine July 26.

In the future, the team wants to do a trial with people who have received an mRNA vaccine, he said. For now, they are testing whether this vaccine can be effective for people who haven’t been vaccinated, he said.

“I’m excited we get a chance to test the vaccine in humans,” he said. “After testing for safety and efficacy, we will monitor the vaccine to see if it does what it’s supposed to in a healthy human population.”

With this vaccine, the team hopes to prevent infection and transmission, he said.

“With the nasal spray, a patient sprays it into their respiratory tract where COVID-19 enters your body,” he said. “This sets up a defense perimeter at the site of the virus entry, which has been very effective in animals, and we hope this can help prevent transmission in humans.”

The vaccine only requires a single dose and can be stored at normal temperatures, McCray said. It can also be produced in large amounts and doesn’t require the use of syringes or needles to administer it, he said.

Kun Li, associate research scientist in pediatrics at the UI Carver College of Medicine, said this vaccine might help in other countries where there are limited resources.

“In places like India and South Africa where there are more people infected and they are experiencing more variants, this could help vaccinate those populations,” Li said. “The majority of the world’s population still needs vaccines.”

According to the Iowa Coronavirus Dashboard as of July 17, 58.1 percent of Johnson County residents and 46.2 percent of people in Iowa are fully vaccinated. According to the Mayo Clinic, 48.7 percent of the U.S. population is fully vaccinated.

These advantages would make it easier to distribute the vaccine to places that don’t have the capacity to store vaccines in ultra-cold freezers, McCray said. The vaccine might also be easier to administer for people who have a fear of needles, he said.

While the available mRNA vaccines are effective, they won’t stop the COVID-19 pandemic, he said.

“The way to stop this pandemic is to have a vaccine that can prevent infection and transmission,” he said. “We can save people from dying using the current vaccines, but we want the virus to go away which is why we need to prevent transmission.”

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